Regenerative ingot-heating furnace with oil burners



R O T N E V m F. S. BLOOM Filed May 23, 1947 A l l l REGENERATIVE INGOT-HEATING FURNACE WITH OIL BURNERS April 18, 1950 @NNI Patented Apr. 18, 1950 REGENERATIVE INGOT-HEATING FURNACE *WITH OIL BURNERS Frederick Stuart Bloom, Mount Lebanon Township, Allegheny County, Pa.

Application May 23, 1941, Serial No. 749,949

3 Claims.

This invention relates to a regenerative furnace and, in particular, to theprovision of oll burners in an ingot-heating furnace ory soaking pit. f

Ingot-heating furnaces are usually installed in banks, i. e., a plurality of heating chambers or pits are constructed side-by-side so as to be accessible` to a common crane. If the furnaces are of the regenerative type, the checker chambers thus have to be placed at oppositeends of the heating chamber proper. 'I'he area above the checker chambers must bc kept clear to permit removal of the furnace cover and to provide working space. These conditions are no obstacle `to the supply of gaseous fuel which is usually delivered from the outerA end of the checker chamber into a port or passage extending over the checkerwork and communicating with the heating chamber. It has not been feasible heretofore, however, to fire regenerative ingot-heating furnaces with liquid fuel because there is no place suitable for the installation of the necessary burners or atomizing nozzles and the pipe connections thereto.

In one type of prior installation where an attempt was made to use liquid fuel for ingot-heatlng furnaces, the burners were placed at the outer ends of the checker chambers and arranged to fire over the checkerwork. This caused deterioration of the roof of the checker chamber because of the excessive temperature created by mixture of the fuel and incoming hot air and the resulting combustion before the gases actually entered the heating chamber. In another type of installation, the burners were so located as to fire directly into the heating chamber through the entry port. With this arrangement, however, it is diiiicult to avoid burning or washing of the ingots by direct impingence of the flame thereon. In both these types of installation, extensive provisions haveto be made for cooling the burners and piping. Because of the dimcultes mentioned, it has generally been considered that prior attempts to utilize oil for firing regenerative ingot-heating furnaces have been failures. y

I have invented a novel regenerative furnace suited for'heating ingots or other purposes, so constructed as to permit the installation and operation of liquid-fuel burners without any of the above diiiiculties orobjectionable results. In

a preferred embodiment, I construct a well between the heating chamber and each checker chamber, communicating with the port leading from the checker chamber to the heating cham- A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanylng drawings illustrating a preferred embodiment. In thedrawings,

Figure 1 is a partial plan view, partly broken away, of a furnace having the invention incorporated therein;

Figure 2 is a vertical section taken along the plane of lineII-II of Figure 1; and

Figure 3 is a cross section taken along the plane of line III-III of Figure 2.

Referring now in detail to the drawings whichare largely diagrammatic, an ingot-heating furnace indicated generally at I0 comprises a heating chamber proper II provided with a removable cover I2 and adapted to receive mgots I3 for heating to rolling temperature. The bottom of the furnace is supported in the usual manner on structural members IIa resting on a suitable foundation.` Ports I4 open into opposite sides of the chamber II providing communication between the latter and checker chambers I5 on opposite ends ofthe heating chamber. Each chamber I5 contains a mass of checkerwork I6 adapted to be connected alternately by suitable reversing valves and flues I'I to a source of air under pressure and a Waste-gas stack.

The construction described so far is largely `conventional and forms no part of my invention.

In order to permit the furnace I0 to be fired with liquid fuel such as oil,lI provide a well I8 extending downwardly from the ports I4 between the heating chamber II and each of the checker chambers I5. The Wells I8 are defined by the sidewalls of the heating chamber and cross walls I 9 in the checker chambers. Inlets 20 open into the bottoms of the wells from the space bctween the checker chambers and below the heating chamber. Upwardly-ring burners 2| are disposed in the bottoms of the wells and are supplied with a mixture of steam and atomized fuel from mixing devices 22 to which steam and oil are supplied by pipe lines 23. 'Ihe inlets 2l have partitions 24 therein which limit the induction of air with the entering fuel.

Assuming that the furnace is being fired from left to right. air supplied through the fines I1 will pass upwardly through the left-hand mass of checker brick i6 which has previously been heated by waste combustion gases and absorb heat therefrom before passing to the heating chamber il through the port il. The mixture of steam and oil discharged upwardly from the bottom of the left-hand well Il. after partial combustion in the well, meets the entering hot air in the port I4 and is thereby swept into the chamber Il. Combustion of the fuel proceeds slowly as the flame and combustion gases pass through the heating chamber toward the righthand port I4 and thence through the other checker chamber to the stack. By restricting the air induced by the entering fuel. I limit the combustion which occurs in the well I8. Ordinarily, I prefer to admit to the well only about 20% of the air required for complete combustion of the fuel. This prevents the temperature in the well from increasing to a value at which the brickwork would deteriorate. As the ascending combustible mixture meets the entering hot air. it is directed by the latter into the heating chamber producing a slowly burning flame therein which does not injure the ingots because, as stated, combustion of the fuel is not completed until about the time the gases flow out through the right-hand port Il. The burners 2i being located at the bottoms of the wells, which are several feet deep, are protected from the entering hot air, the flame in the heating chamber and the combustion gases flowing out through the right-hand port to the stack.

It will be understood that the burners in the two wells are operated alternately, depending on the direction of firing. That is to say, after ring from left to right for the desired period. the left-hand burners are turned off and the righthand burners are turned on simultaneously with the reversal of the flow of air and gases to and from the heating chamber.

It will .be apparent from the foregoing that the invention makes possible the use of liquid fuel for firing regenerative furnaces, without any of the difficulties previously encountered. As a result of the location of the burners in the wells and the restriction of the air induced with the fuel. but little combustion occurs in the well. The fuel mixes with the entering air for further combustion at the mouth of the port so that the roof of the latter is not subjected to excessive temperature. The slowly burning flame which is thus produced in the heating chamber does not cause injury to the surfaces of the ingots by burning or washing. The location of the burners in wells avoids the necessity for special provisions to cool them. By limiting the combustion occuring in the well, the deposit of carbon is minimized.

Although I have illustrated and described but a preferred embodiment of the invention, it will be recognized that changes in the details of construction and operation may be made without departing from the spirit of the invention and the scope of the appended claims.

I claim:

1. A regenerative furnace for heating ingots by means of fuel oil, comprising an ingot heating chamber having ports at opposite ends thereof and a floor to support ingots, a checker chamber spaced from each of said ports. a conduit extending horizontally between each checker chamber and the adjacent port, a well opening into an intermediate portion of the conduit and having sides extending downwardly therefrom substantially below the level of the floor of the ingot heating chamber, a fuel oil burner mounted within the lower portion of each well directed to fire vertically upwardly, a fuel oil supply conduit extending into the well to the burner, means to supply fuel oil to the burner at a predetermined rate, an air inlet opening into each well adjacent the burner and means restricting the amount of air entering the well through said inlet, said restricting means being adjusted to limit the flow of air through said inlet to an amount which will support combustion of about 20% of the predetermined amount of fuel oil simultaneously supplied to the burner.

2. A regenerative furnace for heating ingots without melting them comprising an ingot-heating chamber having ports at opposite ends thereof, a checker chamber spaced from each of said ports, a main air passage connecting each checker chamber and the corresponding port, each main air passage having a portion opening into the corresponding port and extending with substantially uniform cross section straight toward the port, a Well extending transversely of and opening into said portion of each of the main air passages, a fuel oil burner mounted in each well adjacent the end of the well opposite to its opening into the main air passage, and means to supply fuel oil to the bu'rner, each well being open adjacent the burner to admit only sufficient air to the interior of the well to support partial combustion of said fuel oil within the well before it enters the air passage.

3. A regenerative furnace for heating ingots without melting them comprising an ingot-heating chamber having a floor to support the ingots and ports at opposite ends thereof, a checker chamber spaced from each of said ports, a main air passage connecting each checker chamber and the corresponding port, each main air passage having a portion opening into the corresponding port and extending horizontally with substantially uniform cross section straight toward the port, a vertical well opening into said portion of each of the main air passages, upwardly-firing fuel oil burners mounted in each well, the level of the top of the well being substantially above the level of the floor of the heating chamber and the level of all of the burners in the wells being substantially below the level of the floor of the heating chamber, and means to supply fuel oil to the burners, each well being open adjacent the burners to admit only sumcient air to the interior of the well to support partial combustion of said fuel oil within the well before it enters the air passage.

FREDERICK STUART BLOOM.

REFERENCES CITED The following references are of record in the flle of this patent: 

